What is the role of primary treatment in sewage treatment?

Primary treatment in sewage treatment is focused on the physical separation of solids from wastewater, primarily through the process of sedimentation. During this phase, the sewage undergoes a process where heavier solids settle to the bottom of large tanks, forming sludge. This settling process not only removes a significant portion of suspended solids but also helps in reducing the concentration of organic matter present in the wastewater.

This is critical as it lays the groundwork for subsequent treatment stages. By allowing solids to settle, primary treatment effectively reduces the load that must be handled in later treatment phases, such as secondary treatment, which involves biological processes to further break down organic materials. Therefore, this initial stage plays a vital role in improving the overall efficiency of the sewage treatment process by simplifying the subsequent steps needed to treat the wastewater.